at a time when Fox, MSNBC and CNN routinely mix news and entertainment, larding their 24-hour schedules with bloviation fests and marathon coverage of sexual predators and dead celebrities, it’s been “The Daily Show” that has tenaciously tracked big, “super depressing” issues like the cherry-picking of prewar intelligence, the politicization of the Department of Justice and the efforts of the Bush White House to augment its executive power.